A loose electrical cord lying on the floor or on the ground can be a safety hazard, and can be damaged by people walking on the cord or vehicles driving over the cord. Electrical cord roll-up apparatus provide an easy means for storage of electrical cords. Such roll-up apparatus typically have a stationary assembly and a reel assembly rotably mounted on the stationary assembly. The reel assembly can be manually actuated, spring actuated or motor driven.
A plug or socket may be mounted directly onto the stationary assembly or a short “pig tail” cord may be connected to the stationary assembly. The primary electrical cord is electrically connected to the reel assembly which is in turn electrically connected to the stationary assembly, so that the primary electrical cord can be wrapped around the reel assembly without electrical disconnection. A high quality, consistent, wear resistant connection between the stationary assembly and the reel assembly is desirable.
Prior known devices have used radially spaced side contacts on either the stationary assembly or the reel assembly with radially spaced, disk shaped rings on the other assembly to make the electrical connection between the assemblies. The outwardly spaced contacts on such devices will wear more quickly. Rigidly mounted contacts on these devices can provide inconsistent electrical contact if there is end float or bearing looseness between the stationary and reel assemblies. U.S. Pat. No. 4,897,512 to Johnston and U.S. Pat. No. 6,331,121 to Raeford, Sr. disclose roll-up apparatus with substantially rigidly mounted, radially spaced side contacts.
Some prior known devices with radially spaced side contacts use thin, flat, metal contacts. Generally this type of contact projects at an angle between the stationary and reel assemblies. The resilience of the metal provides some pressure of the contact against the rings and limited compensation for relative movement between the stationary and reel assemblies. U.S. Pat. No. 3,929,210 to Cutler et al., U.S. Pat. No. 3,964,490 to Nelms, U.S. Pat. No. 4,300,665 to Arechaga, U.S. Pat. No. 5,701,981 to Marshall et al., and U.S. Pat. No. 6,349,808 to Bryant each disclose an electrical cord roll-up apparatus with thin, flat, metal, radially spaced side contacts.
U.S. Pat. No. 5,700,150 to Morin discloses an electrical cord roll-up apparatus with two axially spaced, thin, flat, metal contacts that project outwardly at an angle from the stationary assembly to contact cylindrical rings on the reel assembly. U.S. Pat. No. 6,273,225 to Park discloses an electrical cord roll-up apparatus having a complex shaft with axial spaced, electrically insulated contact portions. Opposed pairs of thin metal contacts are axially spaced and mounted on the reel assembly, with each contact wrapping partially around a contact portion. The consistency and quality of the electrical contact in the above two devices is limited by the contact pressure which is limited to the resilience of the contact metal.